# BPM, Delay & Reverb Calculator

## How the timing calculation works

A quarter note lasts `60,000 ÷ BPM` milliseconds. Other straight note values are divisions or multiples of that beat: an eighth note is half a beat, while a whole note is four beats.

A dotted note lasts one and a half times its straight value. A triplet note lasts two thirds of the matching straight value. The frequency result is the rate at which that duration repeats: `1,000 ÷ milliseconds` hertz.

The calculator keeps full numeric precision for its calculations, then rounds the visible results to at most three decimal places. Copied values use the same readable rounding.

## Reading delay values

A note-related delay repeats in a stable rhythmic relationship with the tempo. Longer values leave more space between the dry sound and each repeat. Shorter values can make a part feel denser; at very short settings, the ear may hear colour, resonance or comb filtering instead of separate echoes.

Straight, dotted and triplet timings create different placements. A dotted eighth lasts longer than a straight eighth and pushes repeats across the beat. An eighth-note triplet is shorter and places three equal durations in the space normally occupied by two straight eighth notes.

## Reading reverb values

Pre-delay is the gap between the dry sound and the audible start of the reverb. A short pre-delay tends to join the source and room together. A longer pre-delay can preserve the source attack before the tail blooms.

Decay time describes the reverb tail rather than the initial gap. A decay of one beat or one bar is an exact tempo relationship, but it is only a reference. The useful setting also depends on the source envelope, arrangement density, reverb model and how prominent the tail should feel.

## Assumptions and common mistakes

- Bar references assume four quarter-note beats per bar.
- Hertz describes the repetition rate of a timing value; it is not the pitch of the delayed sound.
- Millisecond displays are rounded after calculation. Small display differences between devices can come from different rounding policies.
- A tempo-related value is not automatically the best-sounding value. Move away from the reference when the sound needs a looser, tighter or less obviously rhythmic tail.
- Delay and reverb devices may offer synced note divisions directly. Use milliseconds when a device is in free-time mode or when you want to compare the exact duration.

[Use the interactive calculator on playgrid.cc](https://playgrid.cc/tools/bpm-delay-calculator/)